This project is designed to study the effects of noise exposure on human hearing. We have found that frequency selectivity measurements, as reflected by psychophysical tuning curves (PTC's) are more sensitive to the temporary effects of noise exposure than traditional temporary threshold shift (TTS) measurements. The project is systematically investigating brief exposure to octave bands of noise by determining changes in PTC's centered below, within and above the noise band. We anticipate that PTC's will prove to be more sensitive to noise exposure than TTS.